Oxygen Targets During Mechanical Ventilation in the ICU: A Systematic Review and Meta-Analysis.

Patients admitted to intensive care often require treatment with invasive mechanical ventilation and high concentrations of oxygen. Mechanical ventilation can cause acute lung injury that may be exacerbated by oxygen therapy. Uncertainty remains about which oxygen therapy targets result in the best clinical outcomes for these patients. This review aims to determine whether higher or lower oxygenation targets are beneficial for mechanically ventilated adult patients. DATA SOURCES: Excerpta Medica dataBASE, Medical Literature Analysis and Retrieval System Online, and Cochrane medical databases were searched from inception through to February 28, 2021. STUDY SELECTION: Randomized controlled trials comparing higher and lower oxygen targets in adult patients receiving invasive mechanical ventilation via an endotracheal tube or tracheostomy in an intensive care setting. DATA EXTRACTION: Study setting, participant type, participant numbers, and intervention targets were captured. Outcome measures included "mortality at longest follow-up" (primary), mechanical ventilator duration and free days, vasopressor-free days, patients on renal replacement therapy, renal replacement free days, cost benefit, and quality of life scores. Evidence certainty and risk of bias were evaluated using Grading of Recommendations Assessment, Development and Evaluation and the Cochrane Risk of Bias tool. A random-effects models was used. Post hoc subgroup analysis looked separately at studies comparing hypoxemia versus normoxemia and normoxemia versus hyperoxemia. DATA SYNTHESIS: Data from eight trials (4,415 participants) were analyzed. Comparing higher and lower oxygen targets, there was no difference in mortality (odds ratio, 0.95; 95% CI, 0.74-1.22), but heterogeneous and overlapping target ranges limit the validity and clinical relevance of this finding. Data from seven studies (n = 4,245) demonstrated targeting normoxemia compared with hyperoxemia may reduce mortality at longest follow-up (0.73 [0.57-0.95]) but this estimate had very low certainty. There was no difference in mortality between targeting relative hypoxemia or normoxemia (1.20 [0.83-1.73]). CONCLUSIONS: This systematic review and meta-analysis identified possible increased mortality with liberal oxygen targeting strategies and no difference in morbidity between high or low oxygen targets in mechanically ventilated adults. Findings were limited by substantial heterogeneity in study methodology and further research is urgently required to define optimal oxygen therapy targets.

Oxygen targets in the intensive care unit during mechanical ventilation for acute respiratory distress syndrome: a rapid review.

BACKGROUND: Supplemental oxygen is frequently administered to patients with acute respiratory distress syndrome (ARDS), including ARDS secondary to viral illness such as coronavirus disease 19 (COVID-19). An up-to-date understanding of how best to target this therapy (e.g. arterial partial pressure of oxygen (PaO2) or peripheral oxygen saturation (SpO2) aim) in these patients is urgently required. OBJECTIVES: To address how oxygen therapy should be targeted in adults with ARDS (particularly ARDS secondary to COVID-19 or other respiratory viruses) and requiring mechanical ventilation in an intensive care unit, and the impact oxygen therapy has on mortality, days ventilated, days of catecholamine use, requirement for renal replacement therapy, and quality of life. SEARCH METHODS: We searched the Cochrane COVID-19 Study Register, CENTRAL, MEDLINE, and Embase from inception to 15 May 2020 for ongoing or completed randomized controlled trials (RCTs). SELECTION CRITERIA: Two review authors independently assessed all records in accordance with standard Cochrane methodology for study selection. We included RCTs comparing supplemental oxygen administration (i.e. different target PaO2 or SpO2 ranges) in adults with ARDS and receiving mechanical ventilation in an intensive care setting. We excluded studies exploring oxygen administration in patients with different underlying diagnoses or those receiving non-invasive ventilation, high-flow nasal oxygen, or oxygen via facemask. DATA COLLECTION AND ANALYSIS: One review author performed data extraction, which a second review author checked. We assessed risk of bias in included studies using the Cochrane 'Risk of bias' tool. We used the GRADE approach to judge the certainty of the evidence for the following outcomes; mortality at longest follow-up, days ventilated, days of catecholamine use, and requirement for renal replacement therapy. MAIN RESULTS: We identified one completed RCT evaluating oxygen targets in patients with ARDS receiving mechanical ventilation in an intensive care setting. The study randomized 205 mechanically ventilated patients with ARDS to either conservative (PaO2 55 to 70 mmHg, or SpO2 88% to 92%) or liberal (PaO2 90 to 105 mmHg, or SpO2 ≥ 96%) oxygen therapy for seven days. Overall risk of bias was high (due to lack of blinding, small numbers of participants, and the trial stopping prematurely), and we assessed the certainty of the evidence as very low. The available data suggested that mortality at 90 days may be higher in those participants receiving a lower oxygen target (odds ratio (OR) 1.83, 95% confidence interval (CI) 1.03 to 3.27). There was no evidence of a difference between the lower and higher target groups in mean number of days ventilated (14.0, 95% CI 10.0 to 18.0 versus 14.5, 95% CI 11.8 to 17.1); number of days of catecholamine use (8.0, 95% CI 5.5 to 10.5 versus 7.2, 95% CI 5.9 to 8.4); or participants receiving renal replacement therapy (13.7%, 95% CI 5.8% to 21.6% versus 12.0%, 95% CI 5.0% to 19.1%). Quality of life was not reported. AUTHORS' CONCLUSIONS: We are very uncertain as to whether a higher or lower oxygen target is more beneficial in patients with ARDS and receiving mechanical ventilation in an intensive care setting. We identified only one RCT with a total of 205 participants exploring this question, and rated the risk of bias as high and the certainty of the findings as very low. Further well-conducted studies are urgently needed to increase the certainty of the findings reported here. This review should be updated when more evidence is available.

Correction to: Intraoperative oxygenation in adult patients undergoing surgery (iOPS): a retrospective observational study across 29 UK hospitals.

[This corrects the article DOI: 10.1186/s13741-018-0098-3.].

Intraoperative oxygenation in adult patients undergoing surgery (iOPS): a retrospective observational study across 29 UK hospitals.

Background: Considerable controversy remains about how much oxygen patients should receive during surgery. The 2016 World Health Organization (WHO) guidelines recommend that intubated patients receive a fractional inspired oxygen concentration (FIO2) of 0.8 throughout abdominal surgery to reduce the risk of surgical site infection. However, this recommendation has been widely criticised by anaesthetists and evidence from other clinical contexts has suggested that giving a high concentration of oxygen might worsen patient outcomes. This retrospective multi-centre observational study aimed to ascertain intraoperative oxygen administration practice by anaesthetists across parts of the UK. Methods: Patients undergoing general anaesthesia with an arterial catheter in situ across hospitals affiliated with two anaesthetic trainee audit networks (PLAN, SPARC) were eligible for inclusion unless undergoing cardiopulmonary bypass. Demographic and intraoperative oxygenation data, haemoglobin saturation and positive end-expiratory pressure were retrieved from anaesthetic charts and arterial blood gases (ABGs) over five consecutive weekdays in April and May 2017. Results: Three hundred seventy-eight patients from 29 hospitals were included. Median age was 66 years, 205 (54.2%) were male and median ASA grade was 3. One hundred eight (28.6%) were emergency cases. An anticipated difficult airway or raised BMI was documented preoperatively in 31 (8.2%) and 45 (11.9%) respectively. Respiratory or cardiac comorbidity was documented in 103 (27%) and 83 (22%) respectively. SpO2 < 96% was documented in 83 (22%) patients, with 7 (1.9%) patients desaturating < 88% at any point intraoperatively. The intraoperative FIO2 ranged from 0.25 to 1.0, and median PaO2/FIO2 ratios for the first four arterial blood gases taken in each case were 24.6/0.5, 23.4/0.49, 25.7/0.46 and 25.4/0.47 respectively. Conclusions: Intraoperative oxygenation currently varies widely. An intraoperative FIO2 of 0.5 currently represents standard intraoperative practice in the UK, with surgical patients often experiencing moderate levels of hyperoxaemia. This differs from both WHO's recommendation of using an FIO2 of 0.8 intraoperatively, and also, the value most previous interventional oxygen therapy trials have used to represent standard care (typically FIO2 = 0.3). These findings should be used to aid the design of future intraoperative oxygen studies.

Leadership and management in UK medical school curricula.

Purpose Although medical leadership and management (MLM) is increasingly being recognised as important to improving healthcare outcomes, little is understood about current training of medical students in MLM skills and behaviours in the UK. The paper aims to discuss these issues. Design/methodology/approach This qualitative study used validated structured interviews with expert faculty members from medical schools across the UK to ascertain MLM framework integration, teaching methods employed, evaluation methods and barriers to improvement. Findings Data were collected from 25 of the 33 UK medical schools (76 per cent response rate), with 23/25 reporting that MLM content is included in their curriculum. More medical schools assessed MLM competencies on admission than at any other time of the curriculum. Only 12 schools had evaluated MLM teaching at the time of data collection. The majority of medical schools reported barriers, including overfilled curricula and reluctance of staff to teach. Whilst 88 per cent of schools planned to increase MLM content over the next two years, there was a lack of consensus on proposed teaching content and methods. Research limitations/implications There is widespread inclusion of MLM in UK medical schools' curricula, despite the existence of barriers. This study identified substantial heterogeneity in MLM teaching and assessment methods which does not meet students' desired modes of delivery. Examples of national undergraduate MLM teaching exist worldwide, and lessons can be taken from these. Originality/value This is the first national evaluation of MLM in undergraduate medical school curricula in the UK, highlighting continuing challenges with executing MLM content despite numerous frameworks and international examples of successful execution.